Application of beneficial microorganisms on agriculture

Abstract

Food crisis has increasingly become a main issue discussed worldwide. In addition with the recent fuel price increase and the depletion of oil resources, there is a call for bio-fuel as an alternative, which further competes with food production in the agricultural sector. A sustainable agriculture development is needed to mitigate these issues. The ultimate goal of sustainable agriculture according to the National Research Council of USA is to develop farming systems that are productive, profitable, energyconserving, environmentally-sound, conserving of natural resources, and that ensure food safety and quality. Natural farming may provide a good alternative to solve the issues. The concepts and practices of natural farming make use of a consortium of beneficial microorganisms to improve soil health have originated from Han Kyu Cho and the Korean Natural Farming Association (KNFA) more than 30 years ago. However, this knowledge has only come into the English language in the last one to two decades. The practice is very similar to the technology of effective microorganisms (EM) originated by Professor Teruo Higa, University of the Ryukyus, Okinawa, Japan [1, 2, 6]. EM consists of predominant populations of lactic acid bacteria and yeasts, and smaller numbers of photosynthetic bacteria, actinomycetes and other types of organisms that can be applied as microbial inoculants to increase the microbial diversity of soils and plants. EM shifts the soil microbiological equilibrium in ways that can improve soil quality, soil health, and hence the growth, yield, and quality of the crops. Indeed, soil quality is the key to a sustainable agriculture [6]. Beneficial microorganisms and indigenous microorganisms (IMO) generally refer to a large group of naturally occurring and often unknown or ill-defined microorganisms that interact favorably in soils and with plants to render beneficial effects which are sometimes difficult to predict. While EM usually denotes specific mixed cultures of known, beneficial microorganisms that are being used effectively as microbial inoculants that could exist naturally in soil or added as microbial inoculants to soil where they can improve soil quality, enhance crop production and create a more sustainable agriculture and environment [6]. Upon inoculation of beneficial microorganisms to the soil, they can function as biocontrol agents by controlling or suppressing soil-borne plant pathogens through their competitive and antagonistic activities. However, the use of mixed cultures in this approach has been criticized because it is difficult to demonstrate conclusively which microorganisms are responsible for the observed effects, how the introduced microorganisms interact with the indigenous species, and how these new associations affect the soil plant environment. Thus, the use of mixed cultures of beneficial micro-organisms as soil inoculants to enhance the growth, health, yield, and quality of crops has not gained widespread acceptance by the agricultural research establishment because conclusive scientific proof is often lacking [6]. Natural farming which relies on IMO is considered a type of organic farming. As opposed to conventional farming, organic farming does not use any agrochemicals as fertilizers or pesticides. Instead bio-fertilizers and traditional composting of animal or plant manures are used to provide nutrients for the plants. Therefore, it is a low-input but sustainable cropping system, enabling the natural roles of micro-organism to maintain soil fertility and bio-control of plant pathogens [3,4]. In Malaysia, application of IMO in natural farming has been actively adopted by farmers in at least three states since 2001 through the Asian Productivity Organization [4]. However, some of the local technologies only depend on farm testing and lack scientific results [5]. Thus, it suggested conducting research to verify efficiency and dosage of the products before they are marketed. For example, germination test and soil fertility test could be conducted and data should be interpreted using statistical analysis. Microbial diversity can also be determined using scientific methods such as fatty acid profiling, DNA microarray and polymerase chain reaction (PCR). Apart of application on soil and plant, EM have also been widely applied on animal farmland to improve the management of environmental issues such as to reduce the stinky smell due to animal waste and the number of flies; and also to promote the production of organic fertilizer from animal and plant waste. Application of EM to the feed and drinks of the chickens has also been reported to improve the overall health of the animal [23]. The following sections described the case studies where EM was applied to provide improved growth and yield of the maize plants; as well as to improve the quality of meat and to lower the mortality among the Japanese quails.